The present invention relates to a device for restraining a vehicle from movement from the parked position during the loading and unloading operation at a loading dock.
In the loading and unloading of vehicles parked adjacent a loading dock, heavy equipment such as forklifts and the like are used to facilitate and expedite the loading and unloading operation. It is imperative that the vehicle remain in a fixed abutting position relative to the loading dock to prevent serious accidents to both personnel and equipment. Without proper securement, there is a real potential hazard that the equipment will cause the vehicle to inadvertently move away from the loading dock during the loading or unloading operation so that equipment may be damaged or personnel may be injured.
Previous attempts to employ roadway mounted restraints to prevent the vehicle from prematurely moving away from the loading dock have been largely unsuccessful or have had several shortcomings. Attempts to place wheel blocks underneath and wedged in front of the vehicle""s wheels have been unsuccessful because (1) the blocks are easily lost or damaged, (2) the blocks may not operate effectively due to a slippery road surface from oil, rain, ice or snow, (3) the blocks are awkward to handle and sometimes difficult to remove from the wedged position; (4) the blocks require the dock personnel manipulating the device to be located on the roadway adjacent the dock; thus, care must be exercised by the personnel to avoid being injured by the vehicle. Other attempts to utilize various locking mechanisms to obtain proper securement to the loading dock have had one or more of the following problems: (1) they are incapable of being utilized with a wide variety of truck vehicle designs; (2) they rely on the presence and structural integrity of the vehicle ICC bumper, which may be missing, damaged, or of insufficient strength to restrict vehicle motion; (3) they frequently require substantial structural modifications to the dock facility and are costly to install; (4) oftentimes they are awkward, difficult and time consuming to engage and disengage from the vehicle parked at the dock; and (5) the location of the mechanism at the loading dock interferes with the normal operation of the loading equipment during the loading and unloading operations.
Thus, it is an object of the invention to provide a truck restraining device which is not beset with the shortcomings associated with prior devices.
It is an object of the invention to provide a device which is capable of accommodating vehicles of widely varying configurations and sizes.
It is another object of the invention to provide a device which can restrain a vehicle without an ICC bumper.
A further object of the invention is to provide a device which is compact and has a low profile for accommodating vehicles having low undercarriages.
Another object of the invention is to provide a device which may be readily installed in existing loading docks without extensive structural modifications.
A similar object of the invention is to provide a device which may be readily utilized in conjunction with other loading dock equipment such as dock levelers and the like without interfering with the operation of the loading dock.
A further object of the invention is to provide a device which is not hazardous to either personnel or the vehicle.
Still another object of the invention is to provide a device which may be remotely operated and controlled and which may be effectively secured against unauthorized use.
It is also an object of the invention to provide a device which is simple, sturdy and easy to maintain.
In accordance with one embodiment of the invention, a device is provided for restraining a truck from movement during the loading and unloading thereof while the truck is parked in a driveway adjacent a loading dock. The truck restraining device has a lock assembly comprising a base and a locking arm pivotally mounted to the base for rotating between a retracted inoperative and an extended operative position. In the retracted position, the locking arm is substantially horizontal for permitting the truck to drive over the restraining means whereas, in the extended position, the locking arm extends upwardly for engaging the truck wheels for restraining movement of the truck. The locking arm has a front end adapted to pivotally mount to the base and a rear end adapted to engage the wheel in the extended position.
Means is provided for rotating the locking arm between the retracted and the extended positions. In one embodiment, the rotating means comprises a crank operatively connected to the locking arm by a crank drive shaft and link means. The drive shaft has a first end rigidly connected to the crank and a second end rigidly attached to link means which, in turn, is pivotally attached to the locking arm so that the locking arm rotates in response to the rotation of the crank.
Means is provided for positioning the lock assembly between a distal or forward position and a proximal or rearward position and for assuming an intermediate position disposed between the distal and proximal positions in which the lock assembly engages the wheel. The positioning means comprises a lead screw extending between the distal and proximal positions and disposed substantially perpendicular to the upright wall of the loading dock and means for rotatably driving the lead screw. The locking means is operatively connected to the lead screw for linear movement along the lead screw between the distal and proximal positions in response to the rotation of the lead screw. The preferred driving means is a motor.
Means is provided for controlling the position of the lock assembly between the distal and proximal positions in a programmed manner. The controlling means can: (1) automatically position the lock assembly at the distal position after the locking arm is rotated from the extended position to the retracted position; (2) automatically position the lock assembly at the distal position after the lock assembly has reached the proximal position; (3) automatically deactivate the positioning means when the lock assembly is immobile; (4) automatically deactivate the synchronous motor after the current or the torque of the motor reaches a predetermined value.
These and other features and advantages of the invention will be more readily apparent upon reading the following description of a preferred exemplified embodiment of the invention and upon reference to the accompanying drawings wherein: